[U-Boot] [PATCH 1/9] arm926ej-s: Invalidate instruction cache in flush_cache

Albert ARIBAUD
2013-07-29T07:19:21Z

(although this patch is more than two *years* old, it never got properly
answered to. I am doing so here to make sure future readers know why it
was not applied and won't be.)

Hi Michael,

On Thu, 17 Mar 2011 15:46:55 -0400, Michael Spang
<mspang@csclub.uwaterloo.ca> wrote:

> If U-Boot is loaded from RAM and the OS is loaded into an overlapping
> region, the instruction cache is not coherent when that OS is started.
> We must therefore invalidate the instruction cache in addition to
> cleaning the data cache.
>
> Signed-off-by: Michael Spang <mspang@csclub.uwaterloo.ca>
> ---
> arch/arm/lib/cache.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
> index 30686fe..047786a 100644
> --- a/arch/arm/lib/cache.c
> +++ b/arch/arm/lib/cache.c
> @@ -37,6 +37,8 @@ void flush_cache (unsigned long dummy1, unsigned long dummy2)
> asm("0: mrc p15, 0, r15, c7, c10, 3\n\t" "bne 0b\n" : : : "memory");
> /* disable write buffer as well (page 2-22) */
> asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
> + /* invalidate icache for coherence with cleaned dcache */
> + asm("mcr p15, 0, %0, c7, c5, 0" : : "r" (0));
> #endif
> #ifdef CONFIG_OMAP34XX
> void v7_flush_cache_all(void);

This patch has obviously not been applied, and won't be, because of
two reasons: i) overwriting part of U-Boot when loading the kernel
is a bug which should not be papered over, and ii) if we had to do this
anyway, the right place to do it would have been where the issue might
occur, that is, in the OS boot sequence, not in the cache handling
functions.

Apologies for not properly answering in due time.

Amicalement,
--
Albert.